Date: Fri, 16 Dec 1994 05:50:42 -1000 From: jburka@Glue.umd.edu (Jeffrey C. Burka) Message-Id: <3csd0i$c9q@geog20.umd.edu> Organization: Project Glue, University of Maryland, College Park Subject: Genki spar sizes? Hey, folks...looking for a bit of collective net.wisdom here. One of my winter projects is to build a genki, somewhere in the 13' to 15' wingspan range. It's about time I built a nice big wing, and I want something comparable to or bigger than my 13' Feather III delta. Plans are easy enough to come by; there's a basic set in an old KiteLines article which Nop wrote (Winter '88-'89), though there are a few changes I might make; I've seen loads of neat variants (including Carl's, which the dropped-down spine, and someone else's (not sure whose) where the center spine is slightly longer than the other two, such that the center of the kite is not flat, but comes to a slight point). But right now, that's neither nere nor there. What I haven't seen are spar size suggestions for a kite of the size I'm thinking about. I'd rather build with fiberglass, for cost reasons (unless someone has a way cheap supplier of large diameter carbon!) Does anybody have any suggestions on what size spars I need? Since the kite is bowed, should I avoid having a ferrule near the center of the spreader? How light can I make the battens, and for that matter, the spines? Any discussion or suggestions would be greatly appreciated. Jeff -- |Jeffrey C. Burka | Pithy, insightful quote to be inserted | | | when one occurs to me. *If* one occurs | |jeffy@glue.umd.edu | to me. | = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Thu, 15 Dec 1994 23:42:16 -1000 From: crowell@teleport.com (Carl Crowell) Message-Id: Organization: Kites By Carl Crowell Subject: Re: Genki spar sizes? jburka@Glue.umd.edu (Jeffrey C. Burka) writes: >What I haven't seen are spar size suggestions for a kite of the size I'm >thinking about. for the mo-bigger genki you need mo-bigger spars. actually, my design modifications to the genki allow for the use of .1580 carbon in all the spreaders except the main one, and I use a .35x procomp for the main spreader. If you want to build a 15' genki, I sugest using a .610 (od glass) main spreader if you ever want to fly in wind above 16mph. If you use a traditional genki flare system, i have no idea how strong the verticle spreaders must be. With the flare system that I designed for the Wolf genki, .1580s are fine at genkis 3, 4 and 5 meters wide. This is possible due to the minimizing of compression along the spar. As for your stand-off, remember that they are optional, the kite will fly without them. I use .092 solid carbon rod, and it works great. The kicker in a genki is the spine. You want it to be flexable so that it can bend, but stiff enough to not fold. enjoy ___________________________________________________ email: crowell@teleport.com FTP: ftp.teleport.com/pub/users/crowell WWW: http://www.teleport.com/~crowell Kites By Carl Crowell - O.S.F.M. World Headquarters = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 16 Dec 1994 07:55:41 -1000 From: crowell@teleport.com (Carl Crowell) Message-Id: Organization: Kites By Carl Crowell Subject: Re: Genki spar sizes? salanne@convex.csc.FI (Simo Salanne) writes: >>As for your stand-off, remember that they are optional, the kite will fly >>without them. I use .092 solid carbon rod, and it works great. >How about 2 or 3 - mm, I mean, down to 3rd decimal makes me sick >in kite building... Here in the good ole bass ackward U.S. of A. we have to use inches. Five years of physics, organic chem, molecular biology, etc has taught me to think in metric, but I have to work in these damn inches and feet. Wolf Genki Spars for a 4m (12 feet?) Wolf Genki verical spars: 2mm carbon tube standoffs: 1mm carbon rod Main spreader: 4mm-6mm wrapped carbon tube. howz dat? carl P.S. The Wolf Genki is avaibale for non-comercial private use only. This design is available for unlimited use in a non-comerical manner. This means that you may enter a compitition using this design as long as there is not any financial gain involved. This means you can build all you want, but you can't use them in a sponsored show, etc etc.... blah blah blah.. who would have thunk it. ___________________________________________________ email: crowell@teleport.com FTP: ftp.teleport.com/pub/users/crowell WWW: http://www.teleport.com/~crowell Kites By Carl Crowell - O.S.F.M. World Headquarters = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Fri, 16 Dec 1994 13:13:35 -1000 From: salanne@convex.csc.FI (Simo Salanne) Message-Id: <3ct6uv$gm4@pobox.csc.fi> Organization: STACK Finland Subject: Re: Genki spar sizes? In crowell@teleport.com (Carl Crowell) writes: >As for your stand-off, remember that they are optional, the kite will fly >without them. I use .092 solid carbon rod, and it works great. How about 2 or 3 - mm, I mean, down to 3rd decimal makes me sick in kite building... Simo -- Simo.Salanne@csc.fi STACK Finland = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Date: Sat, 17 Dec 1994 09:14:29 -1000 From: lord@eskimo.com (David Lord) Message-Id: Organization: Eskimo North (206) For-Ever Subject: Re: Genki spar sizes? In article <3csd0i$c9q@geog20.umd.edu>, jburka@Glue.umd.edu (Jeffrey C. Burka) writes: > Hey, folks...looking for a bit of collective net.wisdom here. > > One of my winter projects is to build a genki, somewhere in the 13' to 15' > wingspan range. It's about time I built a nice big wing, and I want > something comparable to or bigger than my 13' Feather III delta. > > Plans are easy enough to come by; there's a basic set in an old KiteLines > article which Nop wrote (Winter '88-'89), though there are a few changes I > might make; I've seen loads of neat variants (including Carl's, which the > dropped-down spine, and someone else's (not sure whose) where the center > spine is slightly longer than the other two, such that the center of the > kite is not flat, but comes to a slight point). But right now, that's > neither nere nor there. > > What I haven't seen are spar size suggestions for a kite of the size I'm > thinking about. I'd rather build with fiberglass, for cost reasons (unless > someone has a way cheap supplier of large diameter carbon!) Does anybody > have any suggestions on what size spars I need? Since the kite is bowed, > should I avoid having a ferrule near the center of the spreader? How light > can I make the battens, and for that matter, the spines? > > Any discussion or suggestions would be greatly appreciated. > > Jeff > > > > -- > |Jeffrey C. Burka | Pithy, insightful quote to be inserted | > | | when one occurs to me. *If* one occurs | > |jeffy@glue.umd.edu | to me. | Jeff Back when Stunt Kite Quarterly was still being published I wrote an article on how to calculate spar sizes for scaled kites. The article included a chart to make the spar selection easy. Anyway if you know the spars used for a smaller Genki and are satisfied with their performance then it is possible to calculate the spar sizes for a scaled version. If you can tell me the original spar sizes and the scale factor for your new kite I will give you the new spar sizes. If you will give me your mailing address I will send you a chart so you can do your own selection. Basically the calculation is that the relative stiffness of the spars relative to the original spars is scale factor to the 4th power(S^4). The relative stiffness values are from measurements of deflection under load. The chart contains most of the available spars. I think that an upcoming issue of Kitelines may contain an article on this subject covering the latest new spars. I have used this method for many scaled kites with always satisfactory results. Dave Lord = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =